This long-awaited second book in John Scalzi’s ‘Lock In’ series is a murder mystery set in a robot fighting league. And yes, it’s worth the wait, says our bookseller Simon McDonald

Years back, John Scalzi released the novella Unlocked: An Oral History of Haden’s Syndrome, which detailed– in the oral history format contemporaneously brought into fashion by World War Z — the onset of a flu-like virus that swept the globe, eventually known as Haden’s Syndrome, which is a devastating meningitis-like disease that leaves its victims “locked inside” their body, able to interact with others only virtually or via sophisticated robots known as “threeps.” Then in 2014 came the first book in the series, Lock In, which introduced Rookie FBI agent and Haden survivor Chris Vance (whose gender is never specified in the text, thus ingeniously leading the publisher to release two versions of the audiobook), and their new partner, Leslie Van. Now Vance and Van are back in Head On, which works perfectly as a standalone sci-fi detective-thriller, but adds much to the world Scalzi began building almost half a decade ago.

When promising Hilketa player Duane Chapman inexplicably dies during a game intended to recruit new investors for the sport, and a high-level league official commits suicide soon afterwards, Vance and Van are brought into the investigation. Hilketa is a violent sport — and that’s putting it mildly, by the way — played by Haden-piloted threeps. The objective of the game is to rip the head off a designated threep and carry it to the goal. Yeah; it’s brutal.

Scazli is less concerned with the mystery — it’s fairly obvious at the midway point who the killer is — but untangling the means and motivations of the killer. The author doesn’t shy away from commentating on prejudice against minorities, disability rights, and the way in which government funding can be taken advantage of, but it never dulls the hilarious banter, or grinds the bullet-fast plot. It’s delicate balance, and Scazli nails it.

Head On is an engaging mix of real-world politics and near-future policing. Filled with detail and imagination, paced with action and witty dialogue, Scalzi takes his readers on a white-knuckle ride but never leaves them for dead. This is science fiction at its absolute best.